What a nonogram clue says
A clue like “3 1” is a sentence about one line: a block of three, a gap, a block of one, and nothing else filled.
How it works
A nonogram is a grid with a clue beside every row and above every column. Each clue lists the blocks of filled cells in that line, in order.
“3 1” says: reading left to right, there is a block of exactly 3 filled cells, then at least one empty cell, then a block of exactly 1. Every other cell in the line is empty.
It is a “there is” sentence. There is a place for the 3 and a later place for the 1 that make it true. The puzzle is to find the one picture where every row sentence and every column sentence is true at once.
Order and gaps
The order of a clue is the order of the blocks. “3 1” and “1 3” are different sentences. The first puts the long block first.
Two blocks always have at least one empty cell between them. If they touched, they would be one block, and the clue would say 4.
A clue of 0 says the whole line is empty.
Rows and columns share cells
Every cell is in one row and one column. Filling it makes a claim in both sentences at once. That is what makes nonograms solvable by logic: a fact you learn from a row becomes a clue for a column.
Worth memorizing
A clue lists the blocks in order.
“3 1” means a 3, then later a 1.
Blocks are separated by at least one empty cell.
Every cell not in a block is empty.
The clue says exactly how many cells are filled.
Practice
0 of 5 rightWhich filling matches the clue 3 1?
In how many ways can the clue 4 fit in this row of 6?
In how many ways can 1 1 1 fit in a row of 5?
Which clue belongs next to row 4?
Which clue belongs above column 2?